ADU in San Bernardino, CA
Junior ADU & Interior Conversion in San Bernardino turns existing square footage - spare bedrooms, basements, attached garages, or underutilized second floors - into permitted rental units without expanding the home’s footprint. In a city where post-WWII tract homes on 7,000-10,000 sq ft lots dominate and rental demand outstrips supply, these conversions deliver the fastest path to income. Call (951) 379-3047 to schedule your free estimate.
We are Ellery ADU Studio, a design-build practice serving San Bernardino from our Inland Empire office. Every project runs under one contract at one written price, with permit-ready drawings included from day one.
Why San Bernardino Homes Are Different
San Bernardino’s housing stock was built for a different era. The flatland neighborhoods - from Del Rosa to Valley College - are filled with 1950s-1970s tract homes on generous lots, most with detached two-car garages or covered carports that sit ready for conversion. But the conditions that make these properties attractive also complicate the work.
Summer temperatures here hit 108-112°F regularly, so garage conversions and interior ADUs need substantially oversized HVAC compared to coastal projects. A mini-split sized for Long Beach will fail on a San Bernardino July afternoon. The Cajon Pass funnels Santa Ana winds through the city, which means roof attachments and flashing details matter more here than in sheltered inland valleys. North of Highland Avenue, properties back up against the San Bernardino National Forest and fall within CAL FIRE Very High Fire Hazard Severity Zones - triggering ember-resistant vents, Class A roofing, and one-hour fire-rated exterior assemblies that add $15,000-$25,000 to what would be a straightforward flatland conversion.
Older homes along the Route 66 corridor and east-side streets frequently sit on slab-on-grade or raised wood-frame foundations that need seismic evaluation before adding square footage this close to the San Andreas Fault. The city’s post-bankruptcy affordable housing crunch has also made ADU production a formal pillar of revitalization, creating political will for a relatively streamlined local permitting path that neighboring cities have not matched.
Our Main San Bernardino Services
Three ADU services have dedicated San Bernardino pages with full pricing, sub-job breakdowns, and neighborhood-specific guidance.
ADU Design & Permitting in San Bernardino
Our permit set is the core product, not an afterthought. For San Bernardino’s 1950s-1970s housing stock, we evaluate existing conditions against current CBC and local amendments, then produce a construction-ready set that includes Title 24 energy calculations, structural calcs for seismic zones, and fire-department plan check when required. The designer and builder are the same entity, so no one can point fingers when a detail needs clarification. ADU Design & Permitting in San Bernardino covers full scope, timeline, and documentation.
Garage Conversion ADU in San Bernardino
Garage conversions are the highest-ROI ADU type in San Bernardino. A typical two-car garage conversion runs $80,000-$120,000 all-in and rents for $1,200-$1,600/month - a return coastal markets cannot touch. We assess slab thickness, existing electrical service, and whether the structure can handle the HVAC load this climate demands. Garage Conversion ADU in San Bernardino has complete pricing and neighborhood notes.
New Detached ADU in San Bernardino
When the existing structure cannot adapt or the lot allows better placement, we design and build new detached units from foundation to final inspection. Setback variances, fire separation requirements, and utility trenching across San Bernardino’s large lots all factor into the permit set and fixed-price contract. New Detached ADU in San Bernardino details sizing, siting, and timeline.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Junior ADU & Interior Conversion in San Bernardino
Junior ADU & Interior Conversion in San Bernardino solves the specific problem of turning existing space into income without the cost or complexity of new construction. In a city where the median home was built in 1963 and many families own more house than they use, converting a basement, spare bedroom, or attached garage into a self-contained unit leverages the existing footprint while avoiding the fire-separation and setback rules that complicate detached builds. Junior ADU & Interior Conversion covers our full design-build process for these projects statewide.
The climate and housing era create distinct challenges here. Summer heat means interior JADUs in poorly insulated wings of older homes need dedicated HVAC, not just a window unit. Seismic considerations affect whether we can open up walls or add plumbing stacks in certain foundation types. And the city’s streamlined ADU pathway - a direct result of its post-bankruptcy housing plan - means permitted interior conversions move faster here than in jurisdictions still treating ADUs as discretionary projects.
Room-to-ADU Conversion
Signs you need it
You have a 250-400 sq ft bedroom suite, den, or former mother-in-law quarters with separate exterior access and want to add a kitchenette and full bath for rental income.
What it costs in San Bernardino
Room-to-ADU conversions in San Bernardino typically run $45,000-$75,000 all-in, including permit-ready drawings, kitchenette rough-in, electrical panel evaluation, and final inspection.
How we do it
We measure existing conditions, produce a Title 24-compliant permit set, coordinate the electrical and plumbing rough-in, then finish to the documented scope under our single contract.
Interior JADU
Signs you need it
You want a smaller, owner-occupied unit inside your existing home - under 500 sq ft, with efficiency kitchen and separate entrance - that qualifies for streamlined California JADU rules.
What it costs in San Bernardino
Interior JADUs in San Bernardino typically cost $35,000-$65,000, reflecting the simpler plumbing tie-ins and the fact that no new exterior envelope work is required.
How we do it
We verify the unit meets JADU owner-occupancy requirements, design the efficiency kitchen and bath layout, pull the ministerial permit, and build to the documented photo record.
What Junior ADU & Interior Conversion Costs in San Bernardino
| Item | Typical range in San Bernardino |
|---|---|
| Room-to-ADU conversion (all-in) | $45,000 - $75,000 |
| Interior JADU (all-in) | $35,000 - $65,000 |
| Above-garage ADU conversion | $65,000 - $110,000 |
Can I convert any room into a Junior ADU in San Bernardino?
No - the space must be within the existing walls of your single-family home, have its own entrance, and meet California’s 500 sq ft JADU size limit. We evaluate your floor plan during the first site visit and tell you within 48 hours whether your layout qualifies.
Does a Junior ADU need its own meter in San Bernardino?
Not for a JADU - California law allows shared utilities with the primary residence, though many owners opt for separate electric sub-meters for easier tenant billing. We specify the approach in your permit set and written scope before work starts.
ADU Site Prep & Utilities in San Bernardino
ADU Site Prep & Utilities in San Bernardino addresses the ground-level work that must happen before walls go up. In a city built on 1950s-1970s lots with aging infrastructure, original electrical panels, undersized sewer laterals, and unconditioned garage slabs are the norm, not the exception. ADU Site Prep & Utilities covers our statewide approach to these critical path items.
The climate and terrain create specific demands. Summer heat and Santa Ana winds mean any new electrical service must account for HVAC loads that exceed coastal standards. Properties near the foothills face CAL FIRE requirements that affect exterior utility routing. And San Bernardino’s large lots - 7,000-10,000+ sq ft - often require longer trench runs for sewer, water, and gas extensions than compact urban infill sites.
Electrical Panel Upgrade
Signs you need it
Your existing panel is rated under 200 amps, has no spare breaker slots, or still runs a Zinsco or Federal Pacific main - all common in San Bernardino’s post-WWII housing stock.
What it costs in San Bernardino
Electrical panel upgrades for ADU prep in San Bernardino typically run $3,500-$7,500, including SCE coordination, permit, and inspection.
How we do it
We verify your service size with Southern California Edison, specify the new panel and sub-panel in the permit set, and coordinate the utility disconnect and reconnect as a single contract item.
Plumbing Lateral
Signs you need it
Your home has original cast-iron or clay sewer lateral from the 1960s-1970s, or the city requires a separate sewer connection for the ADU rather than a shared line.
What it costs in San Bernardino
Plumbing lateral work for ADU site prep in San Bernardino typically costs $4,500-$12,000, depending on trench length across these larger lots and whether the city requires a separate tap.
How we do it
We locate the existing lateral with video inspection, determine if a shared or separate connection is required, then trench, install, and test before any foundation work begins.
What ADU Site Prep & Utilities Costs in San Bernardino
| Item | Typical range in San Bernardino |
|---|---|
| Electrical panel upgrade | $3,500 - $7,500 |
| Plumbing lateral (shared or separate) | $4,500 - $12,000 |
| Foundation and grading (conversion or new) | $8,000 - $25,000 |
Do I need to upgrade my electrical panel for a Junior ADU?
Often yes - adding a kitchenette, dedicated HVAC, and electric water heater to a 1960s-era 100-amp service typically exceeds safe capacity. We assess your actual load during the first site visit and specify the upgrade in your written scope if required.
Who handles the city sewer connection for my ADU in San Bernardino?
We do - our contract includes permit pulling, trenching, installation, and inspection coordination with the San Bernardino Municipal Water Department. You receive a documented photo record of the lateral work and the signed-off inspection card.
Brands We Service in San Bernardino
We specify and coordinate prefab and modular systems from Cover, Dvele, Mighty Buildings, and Boxabl within our single-contract design-build model. Parts and warranty support are stocked through our Inland Empire supply chain, with typical prefab coordination turnaround of 8-12 weeks from permit approval to site delivery. See our brands for full specifications.
Pricing for ADU in San Bernardino, CA
| Service | Typical range in San Bernardino |
|---|---|
| Room-to-ADU conversion | $45,000 - $75,000 |
| Interior JADU | $35,000 - $65,000 |
| Above-garage ADU conversion | $65,000 - $110,000 |
| Electrical panel upgrade | $3,500 - $7,500 |
| Plumbing lateral | $4,500 - $12,000 |
| Foundation and grading | $8,000 - $25,000 |
| Garage conversion ADU (full) | $80,000 - $120,000 |
| CAL FIRE compliance add (foothill zones) | $15,000 - $25,000 |
What pushes price up in San Bernardino: hillside or foothill grading, CAL FIRE zone requirements north of Highland Avenue, asbestos or lead remediation in pre-1978 housing stock, and long utility trench runs across large lots. Every figure above is paired with our written-price guarantee under Haven Standard Clause 1 - the scope is locked at signing, with no door-side upsells.
Neighborhoods We Serve in San Bernardino
We work across San Bernardino’s full footprint, from the flatland tracts to the foothill edges. Crews dispatch from our Inland Empire office with materials staged for same-week starts on approved projects.
- Del Rosa
- Valley College
- Arrowhead
- Mount Vernon
- Seccombe Lane
Service Area - Cities Near San Bernardino
Our Inland Empire crews serve the full San Bernardino-Riverside corridor. Homeowners in Highland, CA often face similar foothill fire-zone requirements. Rialto, CA and Colton, CA share San Bernardino’s post-WWII housing stock but operate under different municipal permitting timelines. Grand Terrace, CA properties typically involve steeper grading and longer utility runs. Each city page has jurisdiction-specific pricing and process notes.
Serving San Bernardino, CA - Our Local Coverage Area
We’re based in the San Bernardino area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU in San Bernardino
San Bernardino’s post-bankruptcy housing plan has created a streamlined ministerial review path for most ADU types - typically 60-90 days from complete submittal to permit issuance, faster than discretionary review in neighboring cities. We track every submittal and correction cycle as part of our permit-set service.
California law (AB 670 and SB 796) prohibits HOAs from outright banning ADUs, but they may impose reasonable design and architectural standards. We review your CC&Rs during the first site visit and flag any provisions that could affect exterior materials, height, or placement.
Yes - permit pulling and inspection coordination are included in every contract. You receive copies of all approved plans, inspection sign-offs, and the final certificate of occupancy. No additional fee, no separate contractor to manage.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What San Bernardino Customers Say
"Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D."The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
- Helena V."The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
- Odette N.